﻿Public Class Form1
  Private Sub CheckBox1_CheckedChanged(ByVal _
          sender As System.Object, _
          ByVal e As System.EventArgs) _
          Handles CheckBox1.CheckedChanged
    If Me.CheckBox1.Checked = True Then
      Me.CheckBox2.Checked = False
      Me.CheckBox3.Checked = False
    End If
  End Sub
  Private Sub CheckBox2_CheckedChanged(ByVal _
          sender As System.Object, _
          ByVal e As System.EventArgs) _
          Handles CheckBox2.CheckedChanged
    If Me.CheckBox2.Checked = True Then
      Me.CheckBox1.Checked = False
      Me.CheckBox3.Checked = False
    End If
  End Sub
  Private Sub CheckBox3_CheckedChanged(ByVal _
          sender As System.Object, _
          ByVal e As System.EventArgs) _
          Handles CheckBox3.CheckedChanged
    If Me.CheckBox3.Checked = True Then
      Me.CheckBox1.Checked = False
      Me.CheckBox2.Checked = False
    End If
  End Sub
End Class
